The present invention relates to a photosensitive body for electrophotography (henceforth may be referred to as simply xe2x80x9cphotosensitive bodyxe2x80x9d) and a manufacturing method for the same. Described in more detail, the present invention relates to an electrophotography photosensitive body and a manufacturing method for the same, having an excellent retention rate due to an improvement of photoconductive materials in a photosensitive layer that is provided on top of a conductive substrate and that contains organic material. The present invention is used in electrophotographic printers, copiers, facsimiles, and the like.
Electrophotography photosensitive bodies must have a function for retaining surface charge in the dark, a function for receiving light and generating charge, and a function for similarly receiving light and transporting the charge. In a single-layer photosensitive body, all of these functions are combined in one layer. In a laminated photosensitive body, layers in which the functions are separated mainly between a layer that contributes to charge generation and a layer that contributes to surface charge retention in the dark and charge transport during light receiving times are laminated.
In order to form the image by an electrophotography method using an electrophotography photosensitive body, a Carlson method is used, for example. This method of image formation is conducted as follows: the photosensitive body is charged by corona discharge in the dark; an electrostatic latent image of text or pictures from the original is formed on the charged surface of the photosensitive body; the electrostatic latent image that is formed is developed by the toner; the toner image that is developed is transferred and fixed onto a support body such as paper and the like. After transferring the toner image, and after removing the charge and removing residual toner and conducting photo discharge, the photosensitive body is ready for reuse.
In the prior art, inorganic photoconductive materials such as selenium, selenium alloy, zinc oxide, or cadmium sulfide, and the like dispersed in a resin binding agent, as well as organic photoconductive materials such as poly-N-vinyl carbazole, polyvinyl anthracene, phthalocyanine compounds or bis azo compounds, and the like dispersed in resin binding agents or vacuum deposited have been used for the photosensitive material of the electrophotography photosensitive body as described above.
Of these organic photoconductive materials, various studies have been done on the purification of phthalocyanine compounds. Of these, mu oxo dimers and mu dimers of phthalocyanines that have, in the center, an element that can have an oxidation state of an oxidation number of +3 or greater (henceforth referred to as xe2x80x9cmulti-oxidative element-containing phthalocyaninexe2x80x9d) are already known. They are described in Phthalocyanines, C. C. Leznoff et al, 1989 (VCH Publishers, Inc.) and the like.
Furthermore, the following references describe 29H, 31H-phthalocyanine titanyl complexes, Capobianchi, A. et al, Sens. Actuators, B (1998), B48 (1xcx9c3), 333xcx9c338, and Scrocco, Marisa et al, Inorg. Chem, (1996), 35 (16), 4788xcx9c4790.
In addition, the following are reported as phthalocyanine dimer compounds having constructions comprising two phthalocyanine rings that are joined via at least one carbon atom, nitrogen atom, or oxygen atom, and a titanium atom: 7, 12:13, 58:22, 27;28, 38-tetraimino-15, 20:30, 5-dinitrilo-12, 28:27, 13-bis (nitrilo isoindole [3] iliridene nitrilometheno [1,2] benzono) tentrabenzo [c, h, n, s] [1,6,12,17] tetraazacyclodocosyne, titanium (+1) derivative, 7,12:13,58:22, 27;28, 38-tetraimino-15, 20:30, 5-dinitrilo-12, 28;27,13-bis(nitrilo isoindole [3] iliridene nitrilometheno [1, 2] benzono) tetrabenzo [c, h, n, s][1, 6, 12, 17] tetraazacyclodocosyne, titanyl complex (henceforth abbreviated as xe2x80x9ctetraazacyclodocosyne complexxe2x80x9d). These compounds are described in the following references, Capobianchi, A. et al. Inorg. Chem. (1993), 32 (21), 4605xcx9c11, Ercolani, Claudio et al, J. Chem. Soc., Dalton Trans. (1990), (6), 1971xcx9c7, Baldini, F. et al, Sens. Actuators, B (1998), B51(1xcx9c3), 176xcx9c180.
As described above, phthalocyanine compounds that contain multi-oxidative elements are known to be used as photosensitive materials for electrophotography photosensitive bodies. Furthermore, various studies have been done with regard to their purification. However, currently, among the impurities contained in multi-oxidative element containing phthalocyanine compounds, the substances that relate to the properties of the electrophotography photosensitive body are not always clear. In other words, although various studies have been presented for various purification methods for multi-oxidative element containing phthalocyanine compounds and for various polymers of phthalonitrile compounds, the relationship between the impurities that are generated during the synthesis of multi-oxidative element containing phthalocyanine compounds and the electrophotography properties, particularly electric potential retention rate, has not always been clear.
The object of the present invention is to clarify this relationship, and to provide an electrophotography photosensitive body with excellent electrophotography properties, particularly electric potential retention. A further object of the present invention is to provide a manufacturing method for an electrophotography photosensitive body, wherein when forming a photosensitive layer by a coating solution, a photosensitive layer with excellent electric potential retention can be formed.
The present inventors conducted intensive study in order to solve the above objects. As a result, it was discovered that the electric potential retention rate was greatly increased when, in addition to phthalocyanine, a phthalocyanine dimer compound within a specified content range was included as the photoconductive material in the photosensitive layer on top of the conductive substrate. The electrophotography photosensitive body of the present invention was completed.
In other words, the present invention is a photosensitive body for electrophotography, having a photosensitive layer on top of a conductive substrate, and the photosensitive layer containing a phthalocyanine compound as a photoconductive material, wherein: the layer containing the phthalocyanine compound has a phthalocyanine dimer compound content of about 100 nmol or greater and about 300 mmol or less for every 1 mol of the phthalocyanine compound.
According to a feature of the present invention, the present invention provides an electrophotographic photosensitive body comprising a photosensitve layer which includes titanyl oxo phthalocyanine and its dimer. Matrix assisted laser desorption/ionization time of flight mass spectrometry of the titanyl oxo phthalocyanine and its dimer, which is incorporated in the photosensitive layer, gives at least a first peak having a mass number of 576 and a second peak having a mass number of 1136. The peak integrated intensity of the second peak being from about 10xe2x88x925% to about 30% of that of a peak integrated intensity of the first peak.
Furthermore, for the manufacture of the above electrophotography photosensitive body, when a coating solution which contains charge generating material contains a phthalocyanine compound and a phthalocyanine dimer compound and the content of the latter is within a specified range with respect to the former, the photosensitive body using this coating solution was discovered to have a greatly improved electric potential retention rate. As a result, the method of the present invention was completed.
In other words, the present invention is a manufacturing method for the above described electrophotography photosensitive body, having a process for forming a photosensitive layer by coating a coating solution containing a charge generating material on top of a conductive substrate, wherein: the coating solution contains a phthalocyanine compound and a phthalocyanine dimer compound; and the phthalocyanine dimer compound content is about 100 nmol or greater and about 300 mmol or less for every 1 mol of the phthalocyanine compound.
With the present invention, xe2x80x9cdimerxe2x80x9d also includes multimers in which one or more phthalocyanines are further bonded to a dimer.
The photosensitive layer in the electrophotography photosensitive body of the present invention includes both the single layer type and laminated type and is not limited to either. Furthermore, the above described coating solution in the manufacture method of the present invention can be used with various coating methods such as a dip coating method or a spray coating method and is not limited to either coating method.
The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements.